German patent publication DE-A-100 30 932 discloses a method and system for updating navigation map data. A vehicle continuously detects its position, e.g. using a Global Positioning System (GPS) receiver, and stores the detected position data. In a continuous or periodic manner or on request basis, the collected position data is transferred to a central database. The collected update data of multiple vehicles is evaluated by a navigation map manufacturer, and updates are made to navigation map data. The updated navigation map data may again be disseminated to navigation map data providers or to users of the navigation maps. This process usually involves a long time interval between navigation map updates.